Calculator



FIG. 1 is a perspective view of a calculator showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is an end elevational view thereof; and

FIG. 4 is a side elevational view thereof; the opposite side being the mirror image of the side shown in FIG. 3.

The rear of the device is substantially planar and unornamented. 

The ornamental design for a calculator, as shown and described. 